Key Value Database Complete Guide

Let us understand what is a Key Value database with examples, advantages, disadvantages and much more. One of the most popular implementations of Key Value concept is the Redis database.

What is a Key Value Database?

A Key-Value database, also popularly known as Key-Value Store, is a data storage model designed for storage, retrieval and managing associative arrays. These Associative Arrays are a type of data structure which is also known as a Dictionary or Hash table. The key-value pair concept is also commonly known as Entity Attribute Value (EAV).

The key-value databases are one of the most flexible types of NoSQL Databases. The traditional databases have predefined schemas with data to be strictly in tables. These Key-Value databases are, therefore, an alternative to many of these kinds of limitations in the conventional databases. These Key Value stored databases do not contain any schema and the data value is opaque.

What is a Key in Key-Value Database?

The key in a key-value pair must be unique. This is that unique identifier that allows you to access the value associated with it. This is similar to the primary key concept in databases.

A key could contain any value; however, every database comes with its own set of characteristics and limitations imposed on a key.

What is a Value in Key-Value Database?

The Value can be retrieved using the Key(identifier) in a key-value store. This could contain values like:

String

Numbers

Lists

Sets

Images

Bit Arrays

Binary Values

Short videos

Sorted Sets

Markup codes such as HTML, XML, JSON

Hyper Log logs

Another key-value pair encapsulated in the form of an object

Types of Key Value Stores

These Key-Value stores have different types of consistency models as below.

Solid – state drive or rotating disk

Eventually consistent

RAM

Ordered

Key Value Database Examples

Voldemorte

Redis

Oracle Berkeley DB

Oracle NoSQL

Aerospike

Key Value Pair Advantages

Availability

Better Performance

Scalability

Flexible Data Modeling

Simplicity

Key Value Database Disadvantages

In-efficient ordinary SQL operations such as Group By or Join

Inappropriate SQL datatype for the value

Unavailability of all SQL constraints such as Foreign Key or Not Null

Extra lines of code

If you have any doubts or any additional points to share about Key Value Databases, please mention them in the comment section below.